The Experts below are selected from a list of 1350 Experts worldwide ranked by ideXlab platform
Yujun Pan - One of the best experts on this subject based on the ideXlab platform.
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Deviation of Spatial Representation and Asymmetric Saccadic Reaction Time in Hemi-Parkinson's Disease.
Frontiers in aging neuroscience, 2018Co-Authors: Dongfang Shen, Ying Zhou, Lixin Liang, Lu Zhang, Wangzikang Zhang, Mingsha Zhang, Yujun PanAbstract:Background: Patients with Parkinson's disease (PD) commonly show spatially asymmetric behaviors, such as veering while attempting to walk in a straight line. While there is general agreement that the lateral motor dysfunction contributes to asymmetric behaviors in PD, it is dispute regarding whether the spatial perception is also biased. In addition, it is not clear whether PD impairs the speed of spatial information process, i.e., the efficiency of information process. Objectives: To assess the Visuospatial Representation and efficiency of spatial information processing in hemi-PD. Methods: Two saccadic tasks were employed: non-spatial cue evoked saccade and spatial cue evoked saccade. In the former task, an identical visual stimulus (appeared on the body mid-sagittal plane) was artificially associated with a fixed saccadic target (left or right) in a given session. In the latter task, subjects were instructed to make a rightward or leftward saccade based on the perceived location of a visual cue (left vs. right side of the body mid-sagittal plane). We estimated the location of subjective straight ahead (SSA) for each subject by using a psychometric fitting function to fit the location judgment results, enabling evaluation of the symmetry of Representation between the left and right hemifields. In addition, since the locations of saccadic targets were same in these two tasks, thus, for each individual subject, the elongated saccadic reaction time (SRT) in the latter task, comparing with the former one, mainly reflects the time spent on judgment of the spatial location of visual cue, i.e., spatial perception. We also assessed the efficiency of spatial perception between two hemispheres, through comparing the normalized SRT (i.e., SRT difference between two tasks) between trials with leftward and rightward judgments. Results: Compared with healthy control subjects (HCs), the SSA was shifted to the contralesional side in both left onset PD (LPD, lesion of right substantia nigra) and right onset PD (RPD, lesion of left substantia nigra) patients. The process of spatial information was significantly longer when a spatial cue appeared in the contralesional hemifield. Conclusions: Patients with hemi-PD showed biased Visuospatial Representation between left and right hemifields and decreased the efficiency of spatial information processing in the contralesional side. Such results indicate that the hemi-PD impairs both spatial Representation and the efficiency of spatial information process, which might contribute to asymmetric behaviors.
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Deviation of Spatial Representation and Asymmetric Saccadic Reaction Time in Hemi-Parkinson’s Disease
Frontiers Media S.A., 2018Co-Authors: Dongfang Shen, Ying Zhou, Lixin Liang, Lu Zhang, Wangzikang Zhang, Mingsha Zhang, Yujun PanAbstract:Background: Patients with Parkinson’s disease (PD) commonly show spatially asymmetric behaviors, such as veering while attempting to walk in a straight line. While there is general agreement that the lateral motor dysfunction contributes to asymmetric behaviors in PD, it is dispute regarding whether the spatial perception is also biased. In addition, it is not clear whether PD impairs the speed of spatial information process, i.e., the efficiency of information process.Objectives: To assess the Visuospatial Representation and efficiency of spatial information processing in hemi-PD.Methods: Two saccadic tasks were employed: non-spatial cue evoked saccade and spatial cue evoked saccade. In the former task, an identical visual stimulus (appeared on the body mid-sagittal plane) was artificially associated with a fixed saccadic target (left or right) in a given session. In the latter task, subjects were instructed to make a rightward or leftward saccade based on the perceived location of a visual cue (left vs. right side of the body mid-sagittal plane). We estimated the location of subjective straight ahead (SSA) for each subject by using a psychometric fitting function to fit the location judgment results, enabling evaluation of the symmetry of Representation between the left and right hemifields. In addition, since the locations of saccadic targets were same in these two tasks, thus, for each individual subject, the elongated saccadic reaction time (SRT) in the latter task, comparing with the former one, mainly reflects the time spent on judgment of the spatial location of visual cue, i.e., spatial perception. We also assessed the efficiency of spatial perception between two hemispheres, through comparing the normalized SRT (i.e., SRT difference between two tasks) between trials with leftward and rightward judgments.Results: Compared with healthy control subjects (HCs), the SSA was shifted to the contralesional side in both left onset PD (LPD, lesion of right substantia nigra) and right onset PD (RPD, lesion of left substantia nigra) patients. The process of spatial information was significantly longer when a spatial cue appeared in the contralesional hemifield.Conclusions: Patients with hemi-PD showed biased Visuospatial Representation between left and right hemifields and decreased the efficiency of spatial information processing in the contralesional side. Such results indicate that the hemi-PD impairs both spatial Representation and the efficiency of spatial information process, which might contribute to asymmetric behaviors
Elizabeth A Buffalo - One of the best experts on this subject based on the ideXlab platform.
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neurons in primate entorhinal cortex represent gaze position in multiple spatial reference frames
The Journal of Neuroscience, 2018Co-Authors: Miriam L R Meister, Elizabeth A BuffaloAbstract:Primates predominantly rely on vision to gather information from the environment, and neurons representing visual space and gaze position are found in many brain areas. Within the medial temporal lobe, a brain region critical for memory, neurons in the entorhinal cortex of macaque monkeys exhibit spatial selectivity for gaze position. Specifically, the firing rate of single neurons reflects fixation location within a visual image (Killian et al., 2012). In the rodents, entorhinal cells such as grid cells, border cells, and head direction cells show spatial Representations aligned to visual environmental features instead of the body (Hafting et al., 2005, Solstad et al. 2008, Sargolini et al., 2006, Diehl et al., 2017). However, it is not known whether similar allocentric Representations exist in primate entorhinal cortex. Here, we recorded neural activity in the entorhinal cortex in two male rhesus monkeys during a naturalistic, free-viewing task. Our data reveal that a majority of entorhinal neurons represent gaze position, and that simultaneously recorded neurons represent gaze position relative to distinct spatial reference frames, with some neurons aligned to the visual image and others aligned to the monkey9s head position. Our results also show that entorhinal neural activity can be used to predict gaze position with a high degree of accuracy. These findings demonstrate that Visuospatial Representation is a fundamental property of entorhinal neurons in primates, and suggest that entorhinal cortex may support relational memory and motor planning by coding attentional locus in distinct, behaviorally relevant frames of reference. SIGNIFICANCE STATEMENT The entorhinal cortex, a brain area important for memory, shows striking spatial activity in rodents through grid cells, border cells, head direction cells, and nongrid spatial cells. The majority of entorhinal neurons signal the location of a rodent relative to visual environmental cues, representing the location of the animal relative to space in the world instead of the body. Recently, our laboratory found that entorhinal neurons can signal location of gaze while a monkey visually explores images. Here, we report that spatial entorhinal neurons are widespread in the monkey, and these neurons are capable of showing a world-based spatial reference frame locked to the bounds of explored images. These results help connect the extensive findings in rodents to the primate.
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neurons in primate entorhinal cortex represent gaze position in multiple spatial reference frames
bioRxiv, 2017Co-Authors: Miriam L R Meister, Elizabeth A BuffaloAbstract:Primates predominantly rely on vision to gather information from the environment, and neurons representing visual space and gaze position are found in many brain areas. Within the medial temporal lobe, a brain region critical for memory, neurons in the entorhinal cortex of macaque monkeys exhibit spatial selectivity for gaze position. Specifically, the firing rate of single neurons reflects fixation location within a visual image (Killian et al., 2012). In the rodents, entorhinal cells such as grid cells, border cells, and head direction cells show spatial Representations aligned to visual environmental features instead of the body (Hafting et al., 2005, Solstad et al. 2008, Sargolini et al., 2006, Diehl et al., 2017). However, it is not known whether similar allocentric Representations exist in primate entorhinal cortex. Here, we recorded neural activity in the entorhinal cortex in two male rhesus monkeys during a naturalistic, free-viewing task. Our data reveal that a majority of entorhinal neurons represent gaze position, and that simultaneously recorded neurons exhibit distinct spatial reference frames, with some neurons aligning to the visual image and others aligning to the monkey9s head position. Our results also show that entorhinal neural activity can be used to predict gaze position with a high degree of accuracy. These findings demonstrate that Visuospatial Representation is a fundamental property of entorhinal neurons in primates, and suggest that entorhinal cortex may support relational memory and motor planning by coding attentional locus in distinct, behaviorally relevant frames of reference.
Patrick R Thomas - One of the best experts on this subject based on the ideXlab platform.
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internal Representation of movement in children with developmental coordination disorder a mental rotation task
Developmental Medicine & Child Neurology, 2004Co-Authors: Peter H Wilson, Paul Maruff, Michael Lloyd Butson, Jacqueline Williams, Jarrad A G Lum, Patrick R ThomasAbstract:Recent studies show that children with developmental coordination disorder (DCD) have difficulties in generating an accurate Visuospatial Representation of an intended action, which are shown by deficits in motor imagery. This study sought to test this hypothesis further using a mental rotation paradigm. It was predicted that children with DCD would not conform to the typical pattern of responding when required to imagine movement of their limbs. Participants included 16 children with DCD and 18 control children; mean age for the DCD group was 10 years 4 months, and for controls 10 years. The task required children to judge the handedness of single-hand images that were presented at angles between 0° and 180° at 45° intervals in either direction. Results were broadly consistent with the hypothesis above. Responses of the control children conformed to the typical pattern of mental rotation: a moderate trade-off between response time and angle of rotation. The response pattern for the DCD group was less typical, with a small trade-off function. Response accuracy did not differ between groups. It was suggested that children with DCD, unlike controls, do not automatically enlist motor imagery when performing mental rotation, but rely on an alternative object-based strategy that preserves speed and accuracy. This occurs because these children manifest a reduced ability to make imagined transformations from an egocentric or first-person perspective.
Dongfang Shen - One of the best experts on this subject based on the ideXlab platform.
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Deviation of Spatial Representation and Asymmetric Saccadic Reaction Time in Hemi-Parkinson's Disease.
Frontiers in aging neuroscience, 2018Co-Authors: Dongfang Shen, Ying Zhou, Lixin Liang, Lu Zhang, Wangzikang Zhang, Mingsha Zhang, Yujun PanAbstract:Background: Patients with Parkinson's disease (PD) commonly show spatially asymmetric behaviors, such as veering while attempting to walk in a straight line. While there is general agreement that the lateral motor dysfunction contributes to asymmetric behaviors in PD, it is dispute regarding whether the spatial perception is also biased. In addition, it is not clear whether PD impairs the speed of spatial information process, i.e., the efficiency of information process. Objectives: To assess the Visuospatial Representation and efficiency of spatial information processing in hemi-PD. Methods: Two saccadic tasks were employed: non-spatial cue evoked saccade and spatial cue evoked saccade. In the former task, an identical visual stimulus (appeared on the body mid-sagittal plane) was artificially associated with a fixed saccadic target (left or right) in a given session. In the latter task, subjects were instructed to make a rightward or leftward saccade based on the perceived location of a visual cue (left vs. right side of the body mid-sagittal plane). We estimated the location of subjective straight ahead (SSA) for each subject by using a psychometric fitting function to fit the location judgment results, enabling evaluation of the symmetry of Representation between the left and right hemifields. In addition, since the locations of saccadic targets were same in these two tasks, thus, for each individual subject, the elongated saccadic reaction time (SRT) in the latter task, comparing with the former one, mainly reflects the time spent on judgment of the spatial location of visual cue, i.e., spatial perception. We also assessed the efficiency of spatial perception between two hemispheres, through comparing the normalized SRT (i.e., SRT difference between two tasks) between trials with leftward and rightward judgments. Results: Compared with healthy control subjects (HCs), the SSA was shifted to the contralesional side in both left onset PD (LPD, lesion of right substantia nigra) and right onset PD (RPD, lesion of left substantia nigra) patients. The process of spatial information was significantly longer when a spatial cue appeared in the contralesional hemifield. Conclusions: Patients with hemi-PD showed biased Visuospatial Representation between left and right hemifields and decreased the efficiency of spatial information processing in the contralesional side. Such results indicate that the hemi-PD impairs both spatial Representation and the efficiency of spatial information process, which might contribute to asymmetric behaviors.
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Deviation of Spatial Representation and Asymmetric Saccadic Reaction Time in Hemi-Parkinson’s Disease
Frontiers Media S.A., 2018Co-Authors: Dongfang Shen, Ying Zhou, Lixin Liang, Lu Zhang, Wangzikang Zhang, Mingsha Zhang, Yujun PanAbstract:Background: Patients with Parkinson’s disease (PD) commonly show spatially asymmetric behaviors, such as veering while attempting to walk in a straight line. While there is general agreement that the lateral motor dysfunction contributes to asymmetric behaviors in PD, it is dispute regarding whether the spatial perception is also biased. In addition, it is not clear whether PD impairs the speed of spatial information process, i.e., the efficiency of information process.Objectives: To assess the Visuospatial Representation and efficiency of spatial information processing in hemi-PD.Methods: Two saccadic tasks were employed: non-spatial cue evoked saccade and spatial cue evoked saccade. In the former task, an identical visual stimulus (appeared on the body mid-sagittal plane) was artificially associated with a fixed saccadic target (left or right) in a given session. In the latter task, subjects were instructed to make a rightward or leftward saccade based on the perceived location of a visual cue (left vs. right side of the body mid-sagittal plane). We estimated the location of subjective straight ahead (SSA) for each subject by using a psychometric fitting function to fit the location judgment results, enabling evaluation of the symmetry of Representation between the left and right hemifields. In addition, since the locations of saccadic targets were same in these two tasks, thus, for each individual subject, the elongated saccadic reaction time (SRT) in the latter task, comparing with the former one, mainly reflects the time spent on judgment of the spatial location of visual cue, i.e., spatial perception. We also assessed the efficiency of spatial perception between two hemispheres, through comparing the normalized SRT (i.e., SRT difference between two tasks) between trials with leftward and rightward judgments.Results: Compared with healthy control subjects (HCs), the SSA was shifted to the contralesional side in both left onset PD (LPD, lesion of right substantia nigra) and right onset PD (RPD, lesion of left substantia nigra) patients. The process of spatial information was significantly longer when a spatial cue appeared in the contralesional hemifield.Conclusions: Patients with hemi-PD showed biased Visuospatial Representation between left and right hemifields and decreased the efficiency of spatial information processing in the contralesional side. Such results indicate that the hemi-PD impairs both spatial Representation and the efficiency of spatial information process, which might contribute to asymmetric behaviors
Ying Zhou - One of the best experts on this subject based on the ideXlab platform.
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Deviation of Spatial Representation and Asymmetric Saccadic Reaction Time in Hemi-Parkinson's Disease.
Frontiers in aging neuroscience, 2018Co-Authors: Dongfang Shen, Ying Zhou, Lixin Liang, Lu Zhang, Wangzikang Zhang, Mingsha Zhang, Yujun PanAbstract:Background: Patients with Parkinson's disease (PD) commonly show spatially asymmetric behaviors, such as veering while attempting to walk in a straight line. While there is general agreement that the lateral motor dysfunction contributes to asymmetric behaviors in PD, it is dispute regarding whether the spatial perception is also biased. In addition, it is not clear whether PD impairs the speed of spatial information process, i.e., the efficiency of information process. Objectives: To assess the Visuospatial Representation and efficiency of spatial information processing in hemi-PD. Methods: Two saccadic tasks were employed: non-spatial cue evoked saccade and spatial cue evoked saccade. In the former task, an identical visual stimulus (appeared on the body mid-sagittal plane) was artificially associated with a fixed saccadic target (left or right) in a given session. In the latter task, subjects were instructed to make a rightward or leftward saccade based on the perceived location of a visual cue (left vs. right side of the body mid-sagittal plane). We estimated the location of subjective straight ahead (SSA) for each subject by using a psychometric fitting function to fit the location judgment results, enabling evaluation of the symmetry of Representation between the left and right hemifields. In addition, since the locations of saccadic targets were same in these two tasks, thus, for each individual subject, the elongated saccadic reaction time (SRT) in the latter task, comparing with the former one, mainly reflects the time spent on judgment of the spatial location of visual cue, i.e., spatial perception. We also assessed the efficiency of spatial perception between two hemispheres, through comparing the normalized SRT (i.e., SRT difference between two tasks) between trials with leftward and rightward judgments. Results: Compared with healthy control subjects (HCs), the SSA was shifted to the contralesional side in both left onset PD (LPD, lesion of right substantia nigra) and right onset PD (RPD, lesion of left substantia nigra) patients. The process of spatial information was significantly longer when a spatial cue appeared in the contralesional hemifield. Conclusions: Patients with hemi-PD showed biased Visuospatial Representation between left and right hemifields and decreased the efficiency of spatial information processing in the contralesional side. Such results indicate that the hemi-PD impairs both spatial Representation and the efficiency of spatial information process, which might contribute to asymmetric behaviors.
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Deviation of Spatial Representation and Asymmetric Saccadic Reaction Time in Hemi-Parkinson’s Disease
Frontiers Media S.A., 2018Co-Authors: Dongfang Shen, Ying Zhou, Lixin Liang, Lu Zhang, Wangzikang Zhang, Mingsha Zhang, Yujun PanAbstract:Background: Patients with Parkinson’s disease (PD) commonly show spatially asymmetric behaviors, such as veering while attempting to walk in a straight line. While there is general agreement that the lateral motor dysfunction contributes to asymmetric behaviors in PD, it is dispute regarding whether the spatial perception is also biased. In addition, it is not clear whether PD impairs the speed of spatial information process, i.e., the efficiency of information process.Objectives: To assess the Visuospatial Representation and efficiency of spatial information processing in hemi-PD.Methods: Two saccadic tasks were employed: non-spatial cue evoked saccade and spatial cue evoked saccade. In the former task, an identical visual stimulus (appeared on the body mid-sagittal plane) was artificially associated with a fixed saccadic target (left or right) in a given session. In the latter task, subjects were instructed to make a rightward or leftward saccade based on the perceived location of a visual cue (left vs. right side of the body mid-sagittal plane). We estimated the location of subjective straight ahead (SSA) for each subject by using a psychometric fitting function to fit the location judgment results, enabling evaluation of the symmetry of Representation between the left and right hemifields. In addition, since the locations of saccadic targets were same in these two tasks, thus, for each individual subject, the elongated saccadic reaction time (SRT) in the latter task, comparing with the former one, mainly reflects the time spent on judgment of the spatial location of visual cue, i.e., spatial perception. We also assessed the efficiency of spatial perception between two hemispheres, through comparing the normalized SRT (i.e., SRT difference between two tasks) between trials with leftward and rightward judgments.Results: Compared with healthy control subjects (HCs), the SSA was shifted to the contralesional side in both left onset PD (LPD, lesion of right substantia nigra) and right onset PD (RPD, lesion of left substantia nigra) patients. The process of spatial information was significantly longer when a spatial cue appeared in the contralesional hemifield.Conclusions: Patients with hemi-PD showed biased Visuospatial Representation between left and right hemifields and decreased the efficiency of spatial information processing in the contralesional side. Such results indicate that the hemi-PD impairs both spatial Representation and the efficiency of spatial information process, which might contribute to asymmetric behaviors
